A steering column of an automotive vehicle generally comprises an inner tube of shaft having one of its end portions linked with a steering wheel actuated by the driver and the other of its end portions linked to mechanical elements, such as a toothed rack. The shaft of the steering column is mounted inside an outer tube via two rolling bearings assemblies. Each of the rolling bearing assemblies generally comprises a rolling bearing, for example a ball bearing, with an outer ring and an inner ring between which rolling elements are mounted and maintained by a cage element.
European patent application EP-A1-1 956 254 discloses a pre-stressed rolling bearing comprising an inner ring, an outer ring provided with a housing and two annular wires arranged in the housing to form raceways, a row of balls disposed between the wires and the inner ring, and a pre-stressing element made from elastic material and axially disposed between a first radial flange of the housing and one of the wires. A second radial flange of the housing is pressed against the other wire so as to exert an axial compression force on the pre-stressing element and to preload the rolling bearing both axially and radially.
It is generally required for such rolling bearings for steering column to work at a friction torque as reduced and as constant as possible. However, it may requested for an automotive application, notably for cars at top end of the range, to increase the friction torque of the steering column compared to those applied for cars at medium or low end of the range. Therefore the driver has to apply a more important torque to the driving wheel, and then feels a robustness sensation of the vehicle. This feeling of conduct contributes to the quality image of a vehicle for a driver.
It is therefore a particular object of the present invention to overcome these aforementioned constraints by providing a rolling bearing of simple design with a reduced number of components that is easy to assemble, economical, able to operate for a long time in both an effective and an economic manner, while guaranteeing a high friction torque.